Oakland Athletics' Yoenis Cespedes runs the bases after hitting a home run off Kansas City Royals' Kelvin Herrera in the eighth inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Yoenis Cespedes runs the bases after hitting a...

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Oakland Athletics' Yoenis Cespedes, right, is congratulated by third base coach Mike Gallego after hitting a home run off Kansas City Royals' Kelvin Herrera in the eighth inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Yoenis Cespedes, right, is congratulated by...

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OAKLAND, CA - MAY 19: Josh Donaldson #20 of the Oakland Athletics hits a sacrifice RBI against the Kansas City Royals during the fourth inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Josh Donaldson #20 of the Oakland Athletics...

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OAKLAND, CA - MAY 19: Eric Sogard #28 of the Oakland Athletics slides into home to score a run against the Kansas City Royals during the fifth inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Eric Sogard #28 of the Oakland Athletics...

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OAKLAND, CA - MAY 19: Ryan Cook #48 of the Oakland Athletics celebrates with Derek Norris #36 after the game against the Kansas City Royals at O.co Coliseum on May 19, 2013 in Oakland, California. The Oakland Athletics defeated the Kansas City Royals 4-3. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Ryan Cook #48 of the Oakland Athletics...

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OAKLAND, CA - MAY 19: Josh Donaldson #20 of the Oakland Athletics catches a foul ball hit off the bat of David Lough #7 of the Kansas City Royals (not pictured) of the Kansas City Royals during the fourth inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Josh Donaldson #20 of the Oakland Athletics...

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OAKLAND, CA - MAY 19: Hideki Okajima #39 of the Oakland Athletics pitches against the Kansas City Royals during the seventh inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Hideki Okajima #39 of the Oakland Athletics...

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OAKLAND, CA - MAY 19: Hideki Okajima #39 of the Oakland Athletics fields a ground ball hit off the bat of Eric Hosmer (not pictured) of the Kansas City Royals during the seventh inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Hideki Okajima #39 of the Oakland Athletics...

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Oakland Athletics' Yoenis Cespedes (52) is congratulated by manager Bob Melvin, left, after hitting a home run off Kansas City Royals' Kelvin Herrera in the eighth inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Oakland Athletics' Hideki Okajima, of Japan, works against the Kansas City Royals in the seventh inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Hideki Okajima, of Japan, works against the...

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Oakland Athletics' Hideki Okajima of Japan works against the Kansas City Royals in the seventh inning of a baseball game Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Hideki Okajima of Japan works against the Kansas...

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Oakland Athletics' Hideki Okajima of Japan works against the Kansas City Royals in the seventh inning of a baseball game Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Hideki Okajima of Japan works against the Kansas...

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OAKLAND, CA - MAY 19: Ryan Cook #48 of the Oakland Athletics celebrates after the game against the Kansas City Royals at O.co Coliseum on May 19, 2013 in Oakland, California. The Oakland Athletics defeated the Kansas City Royals 4-3. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Ryan Cook #48 of the Oakland Athletics...

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OAKLAND, CA - MAY 19: Kelvin Herrera #40 of the Kansas City Royals reacts after giving up a home run to Yoenis Cespedes (not pictured) of the Oakland Athletics during the eighth inning at O.co Coliseum on May 19, 2013 in Oakland, California. The Oakland Athletics defeated the Kansas City Royals 4-3. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Kelvin Herrera #40 of the Kansas City Royals...

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OAKLAND, CA - MAY 19: Billy Butler #16 of the Kansas City Royals argues a called third strike with umpire Cory Blaser #89 during the third inning against the Oakland Athletics at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Billy Butler #16 of the Kansas City Royals...

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OAKLAND, CA - MAY 19: Yoenis Cespedes #52 of the Oakland Athletics rounds the bases after hitting a home run of of Kelvin Herrera #40 of the Kansas City Royals during the eighth inning at O.co Coliseum on May 19, 2013 in Oakland, California. The Oakland Athletics defeated the Kansas City Royals 4-3. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Yoenis Cespedes #52 of the Oakland Athletics...

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Oakland Athletics third baseman Josh Donaldson dives for a foul ball hit by Kansas City Royals' Mike Moustakas in the ninth inning of a baseball game Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics third baseman Josh Donaldson dives for a foul...

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OAKLAND, CA - MAY 19: Derek Norris #36 of the Oakland Athletics scores the game tying run off a sacrifice RBI hit by Coco Crisp (not pictured) during the seventh inning against the Kansas City Royals at O.co Coliseum on May 19, 2013 in Oakland, California. The Oakland Athletics defeated the Kansas City Royals 4-3. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Derek Norris #36 of the Oakland Athletics...

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Oakland Athletics' Derek Norris, left, and Ryan Cook celebrate after they defeated the Kansas City Royals in a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Derek Norris, left, and Ryan Cook celebrate...

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Oakland Athletics' Ryan Cook works against the Kansas City Royals in the ninth inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Ryan Cook works against the Kansas City Royals...

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Oakland Athletics' Eric Sogard slides to score against the Kansas City Royals in the fifth inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. Sogard scored on a single by A's Jed Lowrie. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Eric Sogard slides to score against the Kansas...

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Oakland Athletics' Josh Donaldson swings for an RBI-sacrifice fly off Kansas City Royals' Luis Mendoza in the fourth inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' Josh Donaldson swings for an RBI-sacrifice fly...

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OAKLAND, CA - MAY 19: Yoenis Cespedes #52 of the Oakland Athletics scores a run off a sacrifice fly hit by Josh Donaldson (not pictured) during the fourth inning against the Kansas City Royals at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Yoenis Cespedes #52 of the Oakland Athletics...

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OAKLAND, CA - MAY 19: Alcides Escobar #2 of the Kansas City Royals hits a single against the Oakland Athletics during the third inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Alcides Escobar #2 of the Kansas City Royals...

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OAKLAND, CA - MAY 19: Luis Mendoza #39 of the Kansas City Royals pitches against the Oakland Athletics during the first inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Luis Mendoza #39 of the Kansas City Royals...

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OAKLAND, CA - MAY 19: Chris Getz #17 of the Kansas City Royals score a run against the Oakland Athletics during the third inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Chris Getz #17 of the Kansas City Royals...

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Kansas City Royals' Billy Butler, right, argues a called strike three from home plate umpire Cory Blaser (89) in the third inning of a baseball game against the Oakland Athletics, Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Oakland Athletics' A.J. Griffin works against the Kansas City Royals in the first inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' A.J. Griffin works against the Kansas City...

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Oakland Athletics' A.J. Griffin works against the Kansas City Royals in the first inning of a baseball game Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Oakland Athletics' A.J. Griffin works against the Kansas City...

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OAKLAND, CA - MAY 19: Luis Mendoza #39 of the Kansas City Royals pitches against the Oakland Athletics during the first inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Luis Mendoza #39 of the Kansas City Royals...

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OAKLAND, CA - MAY 19: A.J. Griffin #64 of the Oakland Athletics pitches against the Kansas City Royals during the first inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: A.J. Griffin #64 of the Oakland Athletics...

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OAKLAND, CA - MAY 19: Eric Hosmer #35 of the Kansas City Royals celebrates after hitting an RBI double against the Oakland Athletics during the fifth inning at O.co Coliseum on May 19, 2013 in Oakland, California. (Photo by Jason O. Watson/Getty Images)

Photo: Jason O. Watson, Getty Images

OAKLAND, CA - MAY 19: Eric Hosmer #35 of the Kansas City Royals...

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Kansas City Royals' Luis Mendoza works against the Oakland Athletics in the first inning of a baseball game Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Photo: Ben Margot, Associated Press

Kansas City Royals' Luis Mendoza works against the Oakland...

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Kansas City Royals' Luis Mendoza works against the Oakland Athletics in the first inning of a baseball game on Sunday, May 19, 2013, in Oakland, Calif. (AP Photo/Ben Margot)

Perhaps the biggest need the A's have had all season is for their best player, Yoenis Céspedes, to get back into the swing of things.

His encouraging homestand, which featured numerous hard-hit balls, culminated in a laser-shot of a home run in the eighth inning Sunday, the game-winner as Oakland beat Kansas City 4-3 to sweep the series.

It was the fourth time in Oakland history the team has taken a three-game series by winning each game by one run, and the first time the A's had done so since July 2-4, 1993, against the Yankees.

"I feel so good now," Céspedes said through interpreter Ariel Prieto. "The way I was working every day, I believed everything was going to be fine. I didn't know if it was going to be now or later, but I knew it was going to be good."

Céspedes entered the game batting .198. He singled and scored the A's first run in the fourth inning to go with the solo shot in the eighth, his eighth homer of the year.

Céspedes said he was a slow starter in his eight seasons in Cuba; he always hit under .250 in the first 45 games and finished the season hitting over .300. "I believe what's ahead will be better," he said.

He knew that Kansas City reliever Kelvin Herrera throws hard, so Céspedes was looking only for a hard fastball. "And if it's gone, it's gone," Céspedes said.

"He has a flair for that, no question," A's manager Bob Melvin said. "The guy was throwing 100 mph and he just saw it and hit it."

Melvin said he hopes this gets Céspedes on a roll. "Sometimes, it just takes a couple of hits and it's off to the races," he said.

Céspedes, asked if this might be the start of getting back on track, said simply, "Si."

Each of the A's past 12 homers has been a solo shot, tying the Oakland record for consecutive homers with the bases empty.

A's starter A.J. Griffin walked three men and two of them scored, with the Royals picking up single runs in the third, fourth and fifth innings.

"It's really frustrating. I didn't even make guys work their way on base, and they capitalized on that," Griffin said. "But our guys kept battling."

The A's played from behind most of the day but tied it in the seventh on a gift from the Royals: Derek Norris' leadoff single to center got by rookie center fielder David Lough. Norris wound up at third base on the error, and he scored on a sacrifice fly by Coco Crisp.

"I was about as surprised as a human being could be," Norris said. "I was yelling at the ball to 'Get down, get down,' and when it got past him, I knew I had to kick it into gear and get to third base."

Hideki Okajima made his Oakland debut in the seventh and gave up a double (to Alex Gordon, who went 4-for-5) and an intentional walk.

"I was trying to find him a soft landing spot, and maybe have him come in against the opposing eight-nine hitters," Melvin said. "But today, he had to come in and he was ready."

It was Okajima's first appearance in a big-league game since May 9, 2011, with Boston.